Cyber-enabled operation is needed for smart distribution system implementation. The interaction of cyber and power components will affect system reliability. This paper focuses on developing an analytical reliability model for fault detection, isolation, and service restoration for smart distribution feeders. The impact of end-to-end outage probability of data communication along with sending, receiving, and relaying communication node failures is incorporated into the model. Vulnerability of system to cyber attack as an emerging cause of reliability degradation is also investigated. An optimal placement of fault detectors and switching devices are determined in this work to improve reliability. The sum of customer service interruption cost and investment cost is considered as an objective function to be minimized. Bus 2 of the Roy Billinton test system and a typical 27-node distribution network are used to illustrate the role of communication infrastructure malfunction on the planning problem in a distribution feeder. Results and discussions show the necessity of incorporating communication infrastructure failure into the power distribution system planning problem.